Field of the Invention
The present invention relates to a mechanical timepiece having a mechanical timepiece having a balance-with-hairspring rotation angle control mechanism structured to apply to the balance with hairspring such a force as suppressing against rotation of the balance with hairspring. Also, the invention relates to a mechanical timepiece having a switch adjuster mechanism used to adjust positions of a first contact member and second contact member relative to a near-outer-end portion of the stud-mainspring and a spacing between the first contact member and the second contact member. Furthermore, the invention relates to a mechanical-timepiece adjuster device for adjusting positions of first contact and second contact members relative to a near-outer-portion of the stud mainspring.
Background Information
In the conventional mechanical timepiece, as shown in FIG. 13 and FIG. 14 the mechanical-timepiece movement 1100 (mechanical body) has a main plate 1102 constituting a base plate for the movement. A hand setting stem 1110 is rotatably assembled in a hand-setting-stem guide hole 1102a of the main plate 1102. A dial 1104 (shown by the virtual line in FIG. 14) is attached to the movement 1100.
Generally, a main plate has two opposite sides, one side having a dial is referred to as a xe2x80x9cback sidexe2x80x9d of the movement and the opposite side to the side having the dial is referred to as a xe2x80x9cfront sidexe2x80x9d. The train wheel assembled on the xe2x80x9cfront sidexe2x80x9d of the movement is referred to as a xe2x80x9cfront train wheelxe2x80x9d and the train wheel assembled on the xe2x80x9cback sidexe2x80x9d of the movement is as a xe2x80x9cback train wheelxe2x80x9d.
The hand setting stem 1110 is determined in axial position by a switch device including a setting lever 1190, a yoke 1192, a yoke spring 1194 and a back holder 1196. A winding pinion 1112 is rotatably provided on a guide axis portion of the hand setting stem 1110. When rotating the hand setting stem 1110 in a state the hand setting stem 1110 is in a first hand-setting-stem position closest to an inward of the movement along a rotation axis direction (0 the stage), the winding pinion 1112 rotates through rotation of the clutch wheel. A crown wheel 1114 rotates due to rotation of the winding pinion 1112. A ratchet wheel 1116 rotates due to rotation of the crown wheel 1114. By rotating the ratchet wheel 1116, a mainspring 1122 accommodated in a barrel complete 1120 is wound up. A center wheel and pinion 1124 rotates due to rotation of the barrel complete 1120. An escape wheel and pinion 1130 rotates through rotation of a fourth wheel and pinion 1128, third wheel and pinion 1126 and center wheel and pinion 1124. The barrel complete 1120, center wheel and pinion 1124, third wheel and pinion 1126 and fourth wheel and pinion 1128 constitutes a front train wheel.
An escapement/speed-control device for controlling rotation of the front train wheel includes a balance with hairspring 1140, an escape wheel and pinion 1130 and pallet fork 1142. The balance with hairspring 1140 includes a balance stem 1140a, a balance wheel 1140b and a stud mainspring 1140c. Based on the center wheel and pinion 1124, an hour pinion 1150 rotates simultaneously. A minute hand 1152 attached on the hour wheel 1150 indicates xe2x80x9cminutexe2x80x9d. The hour pinion 1150 is provided with a slip mechanism for the center wheel and pinion 1124. Based on rotation of the hour pinion 1150, an hour wheel 1154 rotates through rotation of a minute wheel. An hour hand 1156 attached on the hour wheel 1154 indicates xe2x80x9chourxe2x80x9d.
The barrel complete 1120 is rotatably supported relative to the main plate 1102 and barrel bridge 1160. The center wheel and pinion 1124, the third wheel and pinion 1126, the fourth wheel and pinion 1128 and the escape wheel and pinion 1130 are rotatably supported relative to the main plate 1102 and train wheel bridge 1162. The pallet fork 1142 is rotatably supported relative to the main plate 1102 and pallet fork bridge 1164. The balance with hair spring 1140 is rotatably supported relative to the main plate 1102 and balance bridge 1166.
The stud mainspring 1140c is a thin leaf spring in a spiral (helical)form having a plurality of turns. The stud mainspring 1140c at an inner end is fixed to a stud ball 1140d fixed on the balance stem 1140a, and the stud mainspring 1140c at an outer end is fixed by screwing through a stud support 1170a attached to a stud bridge 1170 fixed on the balance bridge 1166.
A regulator 1168 is rotatably attached on the balance bridge 1166. A stud bridge 1168a and a stud rod 1168b are attached on the regulator 1168. The stud mainspring 1140c has a near-outer-end portion positioned between the stud bridge 1168a and the stud rod 1168b. 
Generally, in the conventional representative mechanical timepiece, as shown in FIG. 8 the torque on the mainspring torque also decreases while being rewound as the sustaining time elapses from a state the mainspring is fully wound (full winding state). For example, in the case of FIG. 8, the mainspring torque in the full winding state is about 27 gxc2x7cm, which becomes about 23 gxc2x7cm at a lapse of 20 hours from the full winding state and about 18 gxc2x7cm at a lapse of 40 hours from the full winding state.
Generally, in the conventional representative mechanical timepiece, as shown in FIG. 9 the decrease of mainspring torque also decreases a swing angle of the balance with hairspring. For example, in the case of FIG. 9, the swing angle of the balance with hairspring is approximately 240 degrees to 270 degrees when the mainspring torque is 25 gxc2x7cm to 28 gxc2x7cm while the swing angle of the balance with hairspring is approximately 180 degrees to 240 degrees when the mainspring torque is 20 gxc2x7cm to 25 gxc2x7cm.
Referring to FIG. 10, there is shown transition of an instantaneous watch error (numeral value indicative of timepiece accuracy) against a swing angle of a balance with hairspring in the conventional representative mechanical timepiece. Here, xe2x80x9cinstantaneous watch errorxe2x80x9d refers to xe2x80x9ca value representative of fast or slow of a mechanical timepiece at a lapse of one day on the assumption that the mechanical timepiece is allowed to stand while maintaining a state or environment of a swing angle of a balance with hairspring upon measuring a watch errorxe2x80x9d. In the case of FIG. 10, the instantaneous watch error delays when the swing angle of the balance with hairspring is 240 degrees or greater or 200 degrees or smaller.
For example, in the conventional representative mechanical timepiece, as shown in FIG. 10 the instantaneous watch error is about 0 degree to 5 seconds per day (about 0 degree to 5 seconds fast per day) when the swing angle of the balance with hairspring is about 200 degrees to 240 degrees while the instantaneous watch error becomes about xe2x88x9220 seconds per day (about 20 seconds slow per day) when the swing angle of the balance with hairspring is about 170 degrees.
Referring to FIG. 12, there is shown a transition of an instantaneous watch error and a lapse time upon rewinding the mainspring from a full winding state in the conventional representative mechanical timepiece. Here, in the conventional mechanical timepiece, the xe2x80x9cwatch errorxe2x80x9d indicative of timepiece advancement per day or timepiece delay per day is shown by an extremely thin line in FIG. 12, which is obtainable by integrating over 24 hours an instantaneous watch error against a lapse time of rewinding the mainspring from the full winding.
Generally, in the conventional mechanical timepiece, the instantaneous watch error slows down because the mainspring torque decreases and the balance-with-hairspring swing angle decreases as the sustaining time elapses with the mainspring being rewound from a full winding state. Due to this, in the conventional mechanical timepiece, the instantaneous watch error in a mainspring full winding state is previously put forward in expectation of timepiece delay after lapse of a sustaining time of 24 hours, thereby previously adjusting plus the xe2x80x9cwatch errorxe2x80x9d representative of timepiece advancement or delay per day.
For example, in the conventional representative mechanical timepiece, as shown by an extreme thin line in FIG. 12 the instantaneous watch error in a full winding state is about 3 seconds per day (3 seconds fast per day). However, when 20 hour elapses from the full winding state, the instantaneous watch error becomes about xe2x88x923 seconds per day (about 3 seconds slow per day). When 24 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x928 seconds per day (about 8 seconds slow per day). When 30 hours elapses from the full winding state, the instantaneous watch error becomes about xe2x88x9216 seconds per day (about 16 seconds slow per day).
Incidentally, as a conventional balance-with-hairspring swing angle adjusting device there is a disclosure, for example, in Japanese Utility model Laid-open No. 41675/1979 of one having a swing angle adjusting plate to generate over-current each time a magnet of the balance with hairspring approaches by swinging and give brake force to the balance with hairspring.
It is an object of the invention to provide a mechanical timepiece having a balance-with-hairspring rotation angle control mechanism that can control the swing angle of the balance with hairspring to be fallen within a constant range.
Furthermore, an object of the invention is to provide a mechanical timepiece which is less changed in watch error and accurate even after lapse of time from the full winding state.
Furthermore, an object of the invention is to provide a mechanical timepiece having a switch adjuster device used to adjust positions of first contact and second contact members relative to a near-outer-end portion of the stud mainspring and a spacing between the first contact and second contact members.
Furthermore, an object of the invention is to provide a mechanical-timepiece adjuster device for adjusting positions of first contact and second contact members relative to a near-outer-end portion of the stud mainspring.
The present invention is, in a mechanical timepiece structured having a mainspring constituting a power source for the mechanical timepiece, a front train wheel rotating due to rotational force given upon rewinding the mainspring and an escapement/speed-control device for controlling rotation of the front train wheel, the escapement/speed-control device being structured including a balance with hairspring alternately repeating right and left rotation, an escape wheel and pinion rotating based on rotation of the front train wheel and a pallet fork controlling rotation of the escape wheel and pinion based on operation of the balance with hairspring, characterized by comprising: a switch mechanism structured to output an on signal when a rotation angle of the balance with hairspring becomes a predetermined threshold or greater, and an off signal when the rotation angle of the balance with hairspring is not excess of the predetermined threshold; and a balance-with-hairspring rotation angle control mechanism structured to apply such a force as suppressing against rotation of the balance with hairspring when the switch mechanism outputs an on signal.
In the mechanical timepiece of the invention, the switch mechanism is preferably structured to output an on signal when a stud mainspring provided on the balance with hairspring contacts a contact member constituting a switch lever.
Also, in the mechanical timepiece of the invention, the balance-with-hairspring rotation angle control mechanism preferably includes a balance magnet provided on the balance with hairspring and a coil arranged to exert a magnetic force to the balance magnet, and the coil being structured to apply a magnetic force to the balance magnet to suppress rotation of the balance with hairspring when the switch mechanism outputs an on signal, and not to apply a magnetic force to the balance magnet when the switch mechanism outputs an off signal.
By using a balance-with-hairspring rotation angle control mechanism thus structured, it is possible to effectively control the rotation angle of the balance with hairspring of the mechanical timepiece thereby improving accuracy for the mechanical timepiece.
Also, in the mechanical timepiece of the invention, the switch mechanism preferably includes a first contact member and a second contact member, and further comprising an adjuster device for changing a spacing between the first contact member and the second contact member.
Also, in the mechanical timepiece of the invention, the switch mechanism preferably includes a first contact member and a second contact member, and further comprising an adjuster device for simultaneously move the first contact member and the second contact member relative to a rotation center of the balance with hairspring.
Also, in the mechanical timepiece of the invention, the adjuster device preferably includes a switch body-provided rotatable about a rotation center of the balance with hairspring, a switch insulating member arranged slidable relative to the switch body, and a switch spacing adjusting lever having a first contact and a second contact.
Also, in the mechanical timepiece of the invention, the adjuster device preferably includes a switch body provided rotatable about a rotation center of the balance with hairspring, a switch insulating member arranged slidable relative to the switch body, and a switch position adjusting lever having an eccentric portion provided rotatable relative to the switch body and to be fit in an elongate hole of the switch insulating member.